Hello Chris,
A mathematical (and practical) treatment of Multiple Tuning for vertical 
antennas can be found in:

   Radio Antenna Engineering
   by Edmund Laport McGraw Hill NY 1952
   pp. 38-43

This book is obviously out of print, but I could send you photocopies of the 
relevant pages.
73
Andre' N4ICK
***********************************

Christer Andersson wrote:

I would like to hear if anyone have tested the Multiple Tuned Vertical in some 
form.
I have understood that the antenna transforms the feed impedance with a factor 
equal to the square of the number of wires used. E.g.10 wires would raise the 
feed impedance about 100 times.
I'm just rebuilding my LF-station and this antenna looks very interesting. 
However, not much information has been found in my litterature. Links or 
articles would be much appreciated.
73,
Christer / sm6pxj